Automatic or semi-automatic telephone-exchange system.



G. A. BETULANDER & N. G. PALMGREN. AUTOMATIC 0R SEMI-AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPucmou mcn1uLY'e.1s1s. 1,251,955. Patented Jan. 1,1918.

I r a sums-51mm x.

G. A. BETULANDER & N. G. PALMGREN. AUTOMATIC 0R SEMI-AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JULY 6,1915- Pamm a Jan. 1. 918.

3 SHEETS-SHEET 2.

b u m mm wwmm G. A. BETULANDER 6:. N. G. PALMGREN. 7 AUTOMATIC on SEW-AUTOMATIC XE'LEPHONE EXCHANGE svsitm.

APPLICATION FILED JULY 5- 915- 1, 51,955. I Patented Jan. 1,1918.

3 BEIIETSSHEBT 3- necting means.

"Exchange en a m remix-Lea et j enfmomnmfotrnnnrnonn e A ians n} sa mi-mortar IhLMdn residing r terns Vi House, vented. ie Automatic isa speci licliti n. j j r v y The inve tiolfi 'ii 'elates to automatic c1; semi-ant ",n'i'a telephone excl' ange systems in whichjei eiry group sel ecting"stage or sece tion comprisesi li inunbe'r of switching units each includi g iit glut: lity on incoming and; outgoing j uncti anus s, common switchin 1} or selecting mei rns flassociated with the\ incoming'lines anelse atat'e'iconnecting means if cnnections between the tnfor effecting the j l I 1 coming and outgo ng l nes In systems of this kinda connectilonfin a groupselecting stage is effected by first connecting the calling junction line with?agroup-selector ac cessi-ble in common to ill incoming junction lines of the same s'witchiii gunit, this groupselector being then operated to select the wanted group of outgoing lines, whereupon the connection between the calling incoming line and an. idle outgoing line of the group selected is established through separate con- As the group-selectors are used only for setting up the connections the number of such selectors may be very small. For instance it may be. suflicient to provide two group-selectors for every switching unit having ten incoming lines. The object of the present invention is further to reduce the necessary number of group-selectors bybetter utilizing them and to reduce the prob ability of a call not getting through for want of selectors. According to the invention this is attained by making a larger number of switching units accessible to the subscribers lines or the junction lines. For that purpose the junction lines accessible in common to a group of subscribers lines and leading to the first group-selectingstage are led into different switching units and, 'further, the junction lines extending in the same direction from the various switching units of a group-selecting stage are led into different switching units of the next group 1. known a 's ub'scra tjer s Pne; clan only reach one 'ttnnnmronn nxcn nnen SYSTEM. r

n' ajyg hatie access' to ftcj r switelid "er i unction ditgti f'a groupselecting fia ll'a yfi izl fillfith '1 very direction to u its. of ;t e next selecting ea 1 mi 1 ti e systems heretosfiore switc'li ing'nnit ajimlction line only one swl' hing unit in each direction. With this arrangement itlmay be sulficient to provide only. one group-selector for every switching hn'itwith sayte'n incoming lines. For the selectio n ogf 1a disengaged switching unitacinstance;

cording tcgthis invention, all non-engaged incoming lines of a switching unit a are marked as engaged ,during .the' selectin operation within the said unit. 'If require however, two or more group-selectors may be allotted to every switching unit and in this instance a switching unit is not blocked until all grou-pselectors of the same switching unit are simultaneously engaged.

In the accompanying drawings:

Figure 1 is a diagrammatic representation' of a. line arrangement for a 10,000line system according to thisinvention;

Fig. 2 a modification;

Fig. 3 a practical application of the line arrangement of Fig. 2. with relays as connecting elements; and

Fig. 4 a modification of the system shown in Fig. 3.

The same references are used fordesignating corresponding parts of the various figures.

In Fig. 1, L designates the subscribers lines which are grouped together in small groups G G G and larger groups G G In a 10,000-1ine system there are ten large groups G each comprising ten small groups g, each including a hundred subscribers lines. Every group of one hundred subscribers lines has access to a number of junction lines Z Z 1 leading to the first groupsselecting stage. In practice there may be ten such junction lines. It is.to be noticed that all lines are shown as singlewire' lines although in practice they include two-or more Wires. The connecting possi-- bilities are designated in Figs. 1 and 2 by small circles at the crossing points between the' lines which can 'be connected together.

looting and connecting means (selectors and relays) necessary for establishing the connect1ons between the appertannng group w? incoming lines Z Z Z and a number of groups I, II, III'of outgoing junction lines m m m In a system accordi'x'ig to the present invention group of incoming junction lines Z Z Z has associated with it separate selecting means adapted to be used. in common by all the lines of said group. The switching units A A A constitte together the first grcupselecting stage in which the thousands groups G of scri-bers lines are selected.

As will be seen from the drawing every subscribers line has access to three (in practice ten or more) switching units A A A .and each group D D D of three units is allocated to a group G of subscribers lines. The lines Z Z Z common to a group g of subscribers lines may also be connected to units belonging todiflerent groups D D D For instance, thelines Z common to group G, may'extend to the different units A, of the various groups D D D the lines Z of groupG to the units A and the lines Z of grou G to "the units A or the lines .1 of. all t 1e small groups g may extend to the units A the lines Z of the groups 9 to the units A and the lines 3 of the groups g to the units A By connecting the lines 5 a group 9 to units of difi'erent-groups I) we gain the advantage that-all outgoing lines m of the first group-selecting stage made available to every subscribersline and thus a more even distribution of the connections is obtained.

The various groups I, II, III of junction linesm outgoing from the'first group-selecting-stage S extend todifferent groups G of subscribers lines, via: the groups I to group G groups II to group G and groups III to I group G The difierent 1i es m m m of each group 1:,- II or III lea according to the invention to different switching units B B B ofthe second groupselecting stage 5 in which the various hundreds gr'iups g are lected. The various groups I, II, III of junction lines m outgoing from the second group-selecting stage extend in the usual mannerto switching units C constituting the line selecting stage S through which the connection with. the wanted subscribcrs line is completed.

Themodification shown in liig. 2 relates to systems in which the connections between the humming and outgoing junction lines of a grouj -selectlng stage are established over special intermediate lines. Fig. :3 shows only a gi'mip l), of switching units A A A of the first grou reflecting stage and the switching units ll of the Second group-selooting stage. A. number of intermediate lines 7) Ti interposed between every group Z 1 2 and Zjof incoming lines and the out going lines at, every intermei'lintc lino hav ing access to only one outgoing line of each cup l. H and III and the various intermediate lines of the same unit having at their dis 'u'isul di'fies'ent outgoing lines. the intermediate lines of a switching unitnre accessible to the appertaining incoming lines This :n'rangoment is repeated in all group-sclm1 ting stages. As will be seen. very incoming line Z can be connected with any of the outgoing lines on through an intermediate line 7;. The switching units compr "c all apparatus necessary tor establishthe mnmections between the incoming and outgoi g lines Z and m. The provision of intermediate lines therefore, docs not atfeet in any way the principle oi the invention which refers to the arrangement of the incoming and outgoing lines.

Fig. 3 is a diagram of connections of a. groups itching unit with intermediate lines as shown in Fig. The connections are established by ineans of relays, one being provided for each connecting possibility. nus, referring to Fig. :2, there is one relay for each small circle. The selecting meansconsist of relays only. The incomplete switching unit shown in Fig. 3 comprises only twoincoming lines Z and Z two intermediate lines 1 and p and two outgoing lines m and. am of two different numerical groups. The outgoing lines m and m lead to different switching units of the next selecting stage as shown in Fig. 2. The lines are connected. together by means of connecting relays 1, 2, 3 and 4. Every incoming line consists of two talking wires 5 andG, a holding or release Wire 7 and a 'test wire 8. The intermediate lines and the outgoing lines m comprise corresponding wires 9, 10, 11, 12 and 13, 14, 15, 16 respectively. A.l-

lotted to every incoming line is a selector" connecting relay 17 by means of which the calling line can be connected with a selector '18 adapted to be used in common by all in- All.

ing relay 24 has been operated, which corresponds to the first intermediate line 19,, not being accessible, a circuit is now established extending from earth through the .lower relay 74 corresponding to the second intermediate line p back contact 75 of the second relay 24, contact 70 of the first relay 27, resistance 125, coil of'26, contact 06 oi" relay 27 and contact 67 of relay 25. Relay 2G locks itself over its contact 70 and closes a circuit for relay 27 through contact 71 oi relay 25, contact 72 of relay 26 andcontact 67 of relay 25. Relay 27 operates and locks itself over its contact 73 at the same time breaking the circuit for relay at contact 124. A circuit is now established extending from earth through the upper relay 74 corresponding to the first ii'iterinediatc line p 'in the same manner as was the lower relay 74. described above. Upon the energization of relay 74 a circuit is closed ex tendingfrom earth througl'i contact 38 of relay 37, wire 39, contacts 57, 58, 59, 59, 60,

- wire 7 9, an operating winding of the lower relay 3, contact of relay 74, contacts 75, 76, 77, 78, 67, wire 4.1 and contact -12 to the battery. The lower connecting relay 3 is thereby energized. Upon attracting its armature it connects earth to the testing wire 12 of the corresponding intermediate line a -thereby closing a circuit from earth through test wire .12, contact 81 of the lower relay 74, contact 82 of the upper relay 17, wire 83, an operating winding of the upper connecting relay 2, wire 84, contact 85 of relay 74, contacts 75, 76, 77, 78, 67, wire 41 and contact 42 to the battery. The upper connecting relay 2 operates upon the closure of that circuit whereby a circuit is closed extending from earth at the holding wire 7 through a. holding winding of the upper connecting relay 2, contact 86, wire 11 holding winding of the lower connecting relay 3, contact 87 and holding wire 15 to the battery at the next switching unit. A connection is thereby established between the calling line Z and the outgoing line m, of the second group through contacts 88 of relay 2, intermediate line 10 and contacts 89 of relay 3. .4

Upon the energization of the connecting relay 2 the circuit of the relay 17 was broken. The latter denergizes and breaks the circuits of the relays 34 and 37 whereby the selector and the searcher are deprived of current and restored to normal condition.

In the arrangement just described a switching unit is blocked as soon as its .group selector is taken into engagement.

Sometimes, however, it may be suitable to admit a subscriber into a switching unit even if the group-selector is engaged, in which case the latter subscriber has to wait until-the selector is disengaged. The block relay 34, Fig. 3, is then to be operated only when there are two non-efl'ectuated calls within the unit. Fig. 4 shows such an arrangement. It may, of course, preferably be used only in systems having the impulse transmitters controlled from the exchange in such a manner that the impulses are not sent out before the line.

Fig. 4 shows two incoming lines I, and 1 having two connecting relays 1 and 2 and two individual selector connecting relays 90 and 91. The relays 90 are adapted to con nect a calling line to a common line 92,93, 94 and the relays 91 are adapted to connect D '80 a selector is connected to another calling line to a second common line 95, 96, 97. The wires 93, 94 and 96, 97 of said comznon lines can be connected separately by means ofcommon selector connecting relays 98, 99'to the wires 43, 49 leading to the common selector. Two relays 100 and 101 are provided for controlling the circuits of the relays 98'and 99 and the circuits of the block relay 34.

Supposing a subscriber connects his line to the incoming line l, a clrcuit 1s closed extending from earth at the holding wire 7 through said wire 7, contact 29 of relay 1,

contact 30 of relay 2, contact 102 of relay 91, relay 90, contact 103 of relay 90 and contact 104 of relay 100 to the battery 31'. Re-

lay 90 operates and locks itself over its con- 105 tact 105; it also closes a circuit through the holding wire 7, contact 106 of relay 90 and relay 100 to the battery. Relay 100 operates and causes a flow of current from earth through contact 107 of relay 101, contact 108 of relay 100 and relay 98 to the battery. Relay 98 operates and locks itself over its contact 109 and contact 110 of-relay 100. At the same time the calling line isconnected to the selector over contacts 111,

112 of relay 98 and contacts 32, 33 of relay 90. The switching unit is not yet blocked as the circuit of the block relay 34 is open at contact 113 of relay 101.

Supposing now another subscriber connects himself to the Second incoming line Z a circuit is closed from earth at the holding wire 7 of that line through said wire, contacts 29'and 30, contact 114 of relay 90, re-

lay 91, contact 103, contact 115 of relay 101 and contact 116 of relay 100' to the battery.

Relay 91 operates, locks itself overcontact 105 and cuts in relay'101 over, Contact 106.

Relay 99, however, cannot yet be energized as its circuit is open at contact 117 of relay contact 47 of the first relay 19.

negative pole of a battery 31 having: its positi-Ye pole connected to earth. Relay 17 energizes and connects the wires 5 and (3 through contacts 32, to the group selector 18. Atthe same time a block relay 3+ is energized over contact 35 of relay 1?. wl'iereby the testwires 8 of all incoming lines of the switching unit in question are connected to earth through contacts 3tS-and This switching unit is therefore marked as engagedor blocked as long as relay 1? is energized, that is as long as the group-selector is engaged. Those of the incoming lines which .are engaged by a talking connection have their test wires permanently connected to earth at the next. preceding switching, unit. At the closing of contact 35 also a relay 37 is energized causing a flow of current from earth through contact 38, wire 39 and further parallely through contacts 40 of auxi'tiary relays 20, switching relays 19. wire -11 and contact 42 of relay 37 to the battery. whereby all switching relays 19 of the selector are energized.

The group-selector-is now operated by the selectiveimpulses sent overi the line branch 5, while the: line branch (3 is continnmislr connected to earth. At. first a circuit is closed extending: from earth at the line branch (3 through line branch ti, contact- 32, wire 43, contact 44. of relay 22. relay 21, wire 41 and contact 42 to the battery. Relay 21 operates and cuts itself into a locking circuit over its contact 45. At the same time relay 22 is supplied with current from earth through contact '38 of relay 37, Wire 39, contact 46 of relay 2-1 and It operates and locks itself over its contact 48. The

first selective impulse is now sent from earth at the line branch 5 through line branch 5, contact 33, wire 49, contact 50 of relay 2'2, contact 51, of relay 21, contact 52 of the first switching relay 19, contact 53 of the first auxiliary relay 20, relay 20; w'ire 41 and contact 42 to the battery. Relay 20 operates and locks itselforer its contact. 54. The c ircuit of the first switching relay 19 is thereby broken at contact 40 but the relay is maintained energized by thQSBlECtiYe inipulse which now passes through contact n? and relay 19. lVhen the first selective inipulse ceases the first switching relay .19 is deprived of current and releases its armatureQ The nextimpulsc therefore passes through line branch 5. contact 33, Wire 49, contacts 50 and 51, contact at) of the first switching relay 1!) contact of the second switching, relay 19, contact 53 of the second auxiliary relay 20. relay 30, wire ll and contact 2 to the battery. The second auxiliary relay 20 operates with the same result as the first relay 2(). When the second impulse ceases the second relay if) is dei nergzized whereby a path is [prepared for the third selective impulse orer contact at; of the second relay 1!) and soon.

The group-selector having. been set the line branch (3 disctnnicctcd from earth and. consequently. the rontrolling relay 21 is deprived of current and releases its armature. A circuit is thereby closed from through contact; $8 of relay 3?, wire 39, contact 57 of relay :Bl. contact of relay 22. back contacts 5) of all dei nerg'ized switching relays it). contact tit.) of the first energized relay 1 for instance. the third, the second group relay 28, wire 41 and contact 42 to the battery. The second group-relay operates and closes another path for the said current. VlZ. through contact (31. of said group relay and controlling: relay 25 to the battery. At the same time the testing relays Z-l oi the searcher 23 are connected through contacts (32 of the second group-relay to the test. wires it oi, the ontgoinglines m m belonging to the sccond'gronp. An out;. 'oi11g line is marked as engaged it"its test wire 16 is connected, to earth through a contact- (ii-3 ot' a connecting relay -leither in this switching unit or in another. The testing; relays 24 are also connected with the test wires 12 of the intermediate lines 11 and 7.). which are marked as engaged by their test wires being connected to earth through contacts (H- of the connectin; relays 3 or 4-. The searcher 23 therefore sinniltaneously tests both the outgoing lines of the group selected and the intermediate lines.

Upon the energization of the controlling relay 25 those of. the testing relays are energized which correspoiul to engaged outgoing lines or intermediate lines. The circuits ekte-nd from earth either through a contact and closes a circuit for relay 27 through.

contact 71; of relay contact. 72 of relay 2t; and contact 67 of relay 25. Relay 27 operates and locks itsclt' over its contact 73. At the same time relay 26 releases its armature. its circuit ha ring been broken at .the thecontacts 6501* the operated testing re.- lays Provide that only the first testearth lay 101.

100. -Upon the energization of relay 101 the circuit of" the block relay 31 is closed through contact 113 of relay 101 and contact 118 of relay 100, whereby the switching unit is blocked for further calls.

As soon as the first calling subscriber has been connected through to the next selecting stage, the circuit of the corresponding relay 9,0 is broken at contact 29 or 30 whereby said relay 90, and, consequently also relays 100 and 98 are deenergized- The circuit of relay 99 is, therefore, now closed through con tact 117 of relay 100 and contact 119 of re On energizing the relay 99 locks itselfover contacts 109 and 110 and corn nectsthe waiting subscribers line Z to the selector. At the same time the switching unit is disengaged by the circuit of the block relay 34 being broken at contact 118.

'In the arrangement above described it may happen that a subscriber is caused to wait although there are other accessible switching units in the same selecting stage having idle group-selectors. By adding the circuits shown in dotted lines means are provided for blocking a switching unit even if there is only one call in the unit provided that another switching unit can-be reached having an immediately available group-selector. For that purpose a relay 120 is provided which is common to a number of switching units, for instance, the units A, A A of a group D in Fig. 1. The relay 120 is adapted to operate only when the group-selectors of all said units are engaged which may be efiected in any known man her, for instance, by interposing series contacts, one for every selector in the circuit of said relay. The switching unit is then normally blocked for only one call, that is as soon as the selector is engaged, the block relay 3 1 being energized over either of the contacts 121 and 122 and over contact 123 of relay 120. -When all accessible selectors are engaged, however, contact 1:23 is opened so that a second call may be admitted for waiting in any of the units except in those having already two calls which units are blocked by their block relay 34 being energized over contacts 118 and 113.

What We claim is:-

1. In a telephone system, the combination of a plurality of calling lines divided into groups, a plurality of groups of junction lines, the various unction lines of a group being accessible in common to the calling lines of the various groups, means for connecting a calling line to one of the junction lines, a numerical selecting device com mon to the junction lines, means for con necting the Junction line connected to the callin g line to thenuinerical selecting device,

a plurality of outgoing'linesmeans for caus ing the selecting device to establish 1n1t1a l connection between a unctmn and an outell into groups, a plurality of groups ofout iirig lines, common numerical selectinglmean tb which each line of each group of calling lines has access and adapted to he used in commen by all the lines of such groups to select and establish initial connection between an incoming and an outgoing line, means for maintaining the connection bet ween the calling lines and the outgoing line when the selecting means is out ch, a plurality of groups of second outgoing lines, second'nw merical selecting means associated with each group of first outgoing lines and adapted to be used in common by all the lines of said group to select and establish initial. connection with an outgoinglline, and means for maintaining a connection between a first outgoing: line and a second outgoing line after the co:union'selecting means iscut oil.

In a telephone system, thecombimition of a plurality oi? calling lines divided into groups, a plurality of groups of outgoing lines, the various lines of a group of out going lines being accessible to ditf'erent groups of calling lines, common numerical;

selecting means associated with each group of calling lines and adapted to be accessible to all the lines of said group and to select and establishinitial connection with an out-v going line, means for maintaining the connection between a calling line and an outgoing line after the calling selecting means is cut 011', a plurality of groups of second outgoing lines, second numerical. selecting means associated with each group of first outgoing lines and adapted to be used in common by all the lines of such group and to select and establish initial. connection with an outgoing line and means for maintaining the connection between a first. outgoing line and a second outgoing line after the calling selecting means is cut oil".

into a number of switching units, each comprising a plurality of incoming and outgoing lines, means tor connecting said hues and common selecting means associated with the.

incomin lines means for blockin an ennect-ing a calling line to an engaged switch- 111g unit aiter it has been ascertamed that there are no' selecting means immediately 'available in any of a, number of switching units.

6. In a telephone exclmnge system, sWitching means of a groupselecting stage divided into a number of switching units, each com prising a plurality of incoming and outgoing lines, means for connecting said lines, and (20111111011 selecting means associated with the incoming lines, means for blocking an engaged switching unit, means for raising the blocking of a sWit-chingunit when there are no selecting means mmileble in any of a noun her of switching unit and means for fizmll y' blocking a, switching unit when there 71 certain maximum number of non-efl'cctunlcd calls in that unit.

7. In a telephoneexchange system, switcln ing means of a groupselecting stage divided into a number of switching units,ea.cl1 comprising a plurality of incoming and on lines, means for connecting said lines, and common selecting means associated with the incoming lines, means for blocking en. en-

.gaged switching unit, means for connecting a calling line to an engaged switching unit after it has been ascertained that there are no selecting means imn'iediately availablein any of a number of switching units, and means for stopping the connecting operation] untiltlzc selecting means are disengaged.

8. in e telephone exchange system, switch- T10 selecting means nnmediatcly available in any 0.

11. number of switching units, means the connecting operation until selecting means disengaged and means ioz connecting two simultaneously calling lines separately and successively to the common selecting means.

GiilllHLF ANSGARIU'S BETULANDER. Nliiii GUNNAE EALMGEEN. T'Vltnesses GRETA Pmsn, OSCAR GRAHN, 

